174699-77-5Relevant academic research and scientific papers
Chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols
Sawada, Erika,Nakata, Kenya
, p. 371 - 373 (2021/03/16)
In this study, chiral guanidine catalyzed acylative kinetic resolution of racemic 2-bromo-1-arylethanols was achieved with high selectivity. Irrespective of the electronic nature and the substitution patterns on the aromatic rings, a variety of substrates were suitable for this reaction. The branched acyl component was considered to be optimal for obtaining high s-values. The transition state of the reaction was proposed based on the absolute configuration of the obtained product.
Asymmetric synthesis of α-bromohydrins by carrot root as biocatalyst and conversion to enantiopure β-hydroxytriazoles and styrene oxides using click chemistry and SN2 ring-closure
Hosseinzadeh, Rahman,Mohadjerani, Maryam,Mesgar, Sakineh
, p. 583 - 591 (2019/02/17)
In this study we have combined the bioreduction of α-bromoketones using carrot root as biocatalyst and click chemistry for the preparation of enantiopure β-hydroxytriazoles in excellent enantiomeric excesses and yields. Moreover, we have utilized chiral α-halohydrins for the synthesis of enantiopure styrene oxides in very good yields and enantiomeric excesses. Structural assignments of the products were based on their 1H and 13C NMR data and their optical rotations. The enantiomeric excess of the chiral products was obtained by HPLC analysis.
Integration of multiple active sites on large-pore mesoporous silica for enantioselective tandem reactions
Xia, Xuelin,Meng, Jingjing,Wu, Hanxin,Cheng, Tanyu,Liu, Guohua
supporting information, p. 1638 - 1641 (2017/02/10)
Facile construction of a multifunctional heterogeneous catalyst through the assembly of Au/carbene and chiral ruthenium/diamine dual complexes in large-pore mesoporous silica was developed. This enables an efficient one-pot hydration-asymmetric transfer hydrogenation enantioselective tandem reaction of haloalkynes, affording chiral halohydrins with up to 99% enantioselectivity. Combined multifunctionalities, such as substrate-promoted silanol-functionality, BF4? anion-bonding gold/carbene and covalent-bonding chiral ruthenium/diamine active centers, contributed cooperatively to the catalytic performance.
One-Pot cascade hydration-asymmetric transfer hydrogenation as a practical strategy to construct chiral β-adrenergic receptor blockers
Ye, Qunqun,Cheng, Tanyu,Zhao, Yuxi,Zhao, Junwei,Jin, Ronghua,Liu, Guohua
, p. 1801 - 1805 (2015/06/23)
The facile construction of biologically active β-adrenergic receptor agonists/blockers and analogues is a great fundamental and practical challenge in medical chemistry. Herein, we report a hydration-asymmetric transfer hydrogenation cascade to realize the one-pot enantioselective transformation of aromatic haloalkynes into chiral aromatic halohydrins, which can be converted readily into chiral β-adrenergicreceptor blockers. Such a one-pot cascade process involves the Au-catalyzed hydration of aryl-substituted haloalkynes to aryl-substituted α-halomethyl ketones and the Ru-catalyzed asymmetric transfer hydrogenation of aryl-substituted α-halomethyl ketones to aryl-substituted 2-haloethanols. The significant benefits of this procedure are that it provides chiral aromatic halohydrins in high yields, with excellent enantioselectivities, and a wide variety of functional groups are tolerated under mild conditions. The study described herein offers a useful approach to construct chiral β-adrenergic blockers, which is an attractive practical organic transformation that is performed in a one-pot manner.
The Ru-catalyzed enantioselective preparation of chiral halohydrins and their application in the synthesis of (R)-clorprenaline and (S)-sotalol
Lu, Chuanjun,Luo, Zonghua,Huang, Ling,Li, Xingshu
experimental part, p. 722 - 727 (2011/08/06)
The asymmetric transfer hydrogenation of a series of halo-substituted aryl methyl ketones, including those substituted in both α-methyl and aryl rings, was studied for the preparation of chiral halohydrins. Up to 99.7% ee was obtained with 2-chloro-1-(2-chlorophenyl)ethanone as the substrate and Ru-CsDPEN as the catalyst in an HCOONa/H2O system. (R)-Clorprenaline, a drug used in the treatment of respiratory disorders, such as bronchitis and asthma, and (S)-sotalol, a class-III antiarrhythmic compound, were prepared with these chiral halohydrins.
Purification and characterization of a yeast carbonyl reductase for synthesis of optically active (R)-styrene oxide derivatives
Kizaki, Noriyuki,Sawa, Ikuo,Yano, Miho,Yasohara, Yoshihiko,Hasegawa, Junzo
, p. 79 - 86 (2007/10/03)
Optically active styrene oxide derivatives are versatile chiral building blocks. Stereoselective reduction of phenacyl halide to chiral 2-halo-1-phenylethanol is the key reaction of the most economical synthetic route. Rhodotorula glutinis var. dairenensis IFO415 was discovered on screening as a potent microorganism reducing a phenacyl halide to the (R)-form of the corresponding alcohol. An NADPH-dependent carbonyl reductase was purified to homogeneity through four steps from this strain. The relative molecular mass of the enzyme was estimated to be 40,000 on gel filtration and 30,000 on SDS-polyacrylamide gel electrophoresis. This enzyme reduced a broad range of carbonyl compounds in addition to phenacyl halides. Some properties of the enzyme and preparation of a chiral styrene oxide using the crude enzyme are reported herein.
Microbial reduction of ω-bromoacetophenones in the presence of surfactants
Goswami,Bezbaruah,Goswami,Borthakur,Dey,Hazarika
, p. 3701 - 3709 (2007/10/03)
Several ω-bromoacetophenone derivatives 6a-f were reduced to (R)-(-)-2-bromo-1-(phenyl/substituted phenyl) ethanol derivatives 7a-f with whole cell biocatalysts in good yields. The enantiomeric excesses were increased to 95% using an anionic surfactant under an inert atmosphere in an aqueous medium. Copyright (C) 2000 Elsevier Science Ltd.
Process for producing optically active carbinols
-
, (2008/06/13)
The present invention relates to a process for producing optically active halomethyl phenyl carbinols of the formula (1), comprising reducing halomethyl phenyl ketones of the formula (2) using an asymmetric reducing agent obtained from boranes and optically active α-phenyl-substituted-β-amino alcohols of the formula (3) or optically active α-non-substituted-β-amino alcohols of the formula (4). The present invention further relates to a process for producing optically active carbinols, comprising reacting a prochiral keytone with an asymmetric reducing agent obtained from optically active β-amino alcohols of the formula (5), a metal boron hydride and Lewis acid or lower dialkyl sulfuric acid. All of the formulas (1) to (5) are the same as shown in the specification.
A practical synthesis of (R)-3-chlorostyrene oxide starting from 3- chloroethylbenzene
Tanaka, Ken,Yasuda, Mari
, p. 3275 - 3282 (2007/10/03)
A novel and practical synthesis of (R)-3-chlorostyrene oxide (-)-1 was achieved starting from commercially available 3-chloroethylbenzene 3. Enantiopure (-)-3-chlorostyrene bromohydrin (-)-5 was obtained by the treatment of racemic (±)-5 with lipase QL in the presence of acylating reagents. 3-Chloro-α,β-dibromoethylbenzene 4, a precursor of (±)-5, was synthesized via the expeditious bromination of 3 which was developed by these authors.
Process for the preparation of optically active 2-halo-1-(substituted phenyl) ethanol
-
, (2008/06/13)
The present invention provides an industrially advantageous process for the preparation of an optically active 2-halo-1-(substituted phenyl)ethanol useful as medicines, agricultural chemicals or as intermediates thereof; and a simple process for the prepa
